DES set to release study on nonpoint nitrogen pollution

PORTSMOUTH — By the end of this month communities along Great Bay will have comprehensive information at their disposal about nonpoint nitrogen pollution in the estuary.

Aaron Sanborn

PORTSMOUTH — By the end of this month communities along Great Bay will have comprehensive information at their disposal about nonpoint nitrogen pollution in the estuary.

On May 16, the N.H. Department of Environmental Services will release a draft copy of "The Great Bay Nitrogen Nonpoint Source Study." The study is the end result of two years of comprehensive work by DES and communities along the Great Bay estuary. Ted Diers, Watershed Management Bureau administration, said the study will be the most detailed look at nonpoint nitrogen pollution in the bay to date.

"It's a very comprehensive study," he said.

Increased nitrogen in the estuary has been blamed for the loss of eelgrass, a critical habitat for fish and other marine species.

Nonpoint sources such as septic systems, fertilizer, pet and livestock waste and stormwater runoff have been identified as contributing to 68 percent of the bays nitrogen load. Diers said the study breaks the nonpoint nitrogen load down into four categories.

First is atmospheric deposition, which is nitrogen that comes via air, mostly through fossil fuels and rain and snow, according to Diers.

Second is human waste, he said, and this is mostly nitrogen from septic systems. Third is animal waste and Diers said this will include nitrogen from farm and domestic animals. The fourth category is fertilizers.

Diers said the study tracks these various sources through different landscapes and eventually into the bay.

"We broke the data down into sub-watersheds that empty into the bay and by the individual towns and cities," he said.

While the release of the report is a milestone in efforts to understand and combat pollution in Great Bay, Diers said the study is still a work in progress,

"We're putting it out there for public comment," he said. "We're asking folks to take a look at it and tell us what they think."

Diers credited communities along the bay for stepping up and helping DES with the study. He said the communities provided DES with various forms of data, including number of registered dogs and cats.

Fertilizer information was collected by sending surveys out to owners of golf courses, turf fields and baseball fields, according to Diers. He said the survey received about a 50 percent response date.

The University of New Hampshire Cooperative Extension also assisted in data collection, Diers said.

"We're hoping people will take a look at this and understand what the priorities should be for addressing nonpoint pollution sources," Diers said. "We're looking for the best results at the lowest costs."

Diers said that while the study will break things down by watersheds and communities, it will not have information on nonpoint sources from specific sites. "It's not site specific," he said, "but it's still much better than anything we've ever had before in understanding these sources."

Diers noted that UNH is also doing some independent "hot spot" study on nonpoint nitrogen pollution that he believes will be helpful.

Exeter Public Works Director Jennifer Perry thinks the report will be helpful in public education efforts.

The town is already focusing on educating the public about stormwater pollution and Perry said the report could point out additional steps the public could take to reduce other nonpoint nitrogen pollution.

"It will help us to focus our efforts," she said. "If we find things that can easily be controlled, then we'll want to use that information to improve things."

Perry added that it will also be a benefit to have a report that just focuses on nonpoint nitrogen pollution. "I'm really looking forward to reading it," she said. "I think it will be interesting to learn from."

Diers said public education is a major component of the study, which he hopes will bring more attention to nonpoint pollution control. "It shows this is not strictly a wastewater treatment plant problem, it's a problem that impacts all of us," he said. "I'm hoping the average homeowner or person who lives in the community will see themselves in this report somewhere."

Nitrogen pollution from wastewater treatment facilities along the Great Bay estuary have been the dominant point of discussion to date in efforts to clean up the bay, largely because of high cost estimates to upgrade and build new wastewater treatment plants to meet new federal mandates to reduce nitrogen emissions.

Both Exeter and Newmarket have already committed to EPA permits that have given them a certain amount of time to build new wastewater treatment plants and up to 15 years to reduce to 3 milligrams per liter the amount of nitrogen they release into the estuary during the treatment process.

While Exeter and Newmarket have accepted their wastewater treatment plant permits, Portsmouth, Dover and Rochester are advocating for a less stringent nitrogen release limit of 8 milligrams per liter, and filed litigation against the EPA, challenging the science behind the permits.

Diers said DES may do a new peer review of the science with these communities, but nothing official has been decided. He said DES has an agreement with the three communities on how to move forward with a peer review, if they choose to go down that path.

"Our preference would be to take an alternative approach to move forward," Diers said.

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